This invention relates to metal connectors for tying together wood members in existing wood structures, and in particular, holding down roof structures against high winds including hurricanes.
In warm climates that are prone to hurricanes, existing single-family houses are typically constructed of light-framed timber. Newer houses have timber stud walls (double wall construction) and timber roof framing with plywood or wood slats. Most of the roof rafters or trusses are not attached to the exterior walls with metal hurricane fasteners. Older houses are usually of single-wall construction with timber-roof framing and non-structural corrugated metal roofing. (See Structural Engineers Association, 1993, p. III-22).
Studies of the damage that the 1992 Hurricane Iniki caused in Kauai, Hawaii, showed that there was extensive loss of roof covering (wood and asphalt shingles, sheet metal, and clay tiles), and sheathing (plywood, tongue-and-groove decking, and metal decking) due to high wind and inadequate attachment. The failed attachments were at the nailing of the roof covering to the sheathing; the stapling of the plywood sheathing; the nailing of metal decking to the battens and the battens to the purlins (trusses); and the nailing and splicing of tongue-and-groove decking. This caused dangerous wind-blown debris and resulted in extensive water damage to the buildings"" contents. Many of the failed connections were xe2x80x9ctoe-nailedxe2x80x9d together, (See Structural Engineers Association, 1993, p. III-22).
Engineers have recommended that all houses being built in Hawaii be in compliance of the current (Building) Code and the continuous load transfer path from roof to foundation should be integrated into all stages of building. Use of (prior art) hurricane clips does not, in and of itself, ensure successful building performance. (See FEMA publication FIA-23 p. 80).
Prior to this invention, the outside wall sheathing had never been used before to form a continuous load transfer path from the roof to foundation. When building houses in a tropical climate, house foundations are very shallow or lacking completely. This invention uses the outside wall sheathing to tie the rafter, top plate, and outside wall together in order to resist uplift forces.
Recent unpublished research on wooden building performance during earthquakes shows that the outside wall sheathing is the most important structural member. If the sheathing comes loose from the wall when a building is shaken during earth tremors, the building can collapse. This invention helps hold the sheathing to the outside wall. None of the prior art holds the outside sheathing to the wall.
A number of connectors have been developed to tie together the roof rafter and the top plate, but these previous connectors were made to be used during construction of the structure. These connectors cannot be retro-fitted to existing structures without extensive dismantling or damage to inside wall board or outside trim. Prior tie connectors are also limited to the number of roofing and structural members that can be tied together.
The roof lock in U.S. Pat. No. 1,452,599 to Hames, March 1922, and the dock bracket in U.S. Pat. No. D.290,223 to Westerheim, June 1987 did not tie the rafter to the top plate and outside sheathing. The hurricane tie in U.S. Pat. No. 4,714,372, December 1987, and snugging connector in U.S. Pat. No. 4,896,985, January 1990, both to Commins, can tie the rafter to the top plate in the skeleton structural framework of new construction. They can not be used as a retrofit on existing houses; they did not tie the sheathing to the top plate and rafter; they did not go around the frieze board; they did not tie into a stud or top plate directly underneath a rafter; and they did not tie together two 2xc3x974""s of the top plate.
The bearing connector in U.S. Pat. No. 5,109,646, May 1992, to Colonias et al. is used to carry roof loads, but can tie together a rafter, top plate, and two 2xc3x974""s of the top plate together in the skeleton structural framework of new construction. This connector can not be used as a retrofit on existing houses; it did not tie the sheathing to the top plate and rafter; it did not go around the frieze board; and it did not tie into a stud or top plate directly underneath a rafter.
The building construction ties in U.S. Pat. No. 2,300,113, to Faber, October 1942, can tie the rafter to the joist and wall stud in the skeleton structural framework of new construction. They can not be used as retrofit on existing houses; they did not tie the sheathing to the top plate and rafter; they did not tie the rafter and top plate together; they did not go around the frieze board; and they did not tie together two 2xc3x974""s of the top plate.
The free gusset metal ledger hanger in U.S. Pat. No. 4,353,664, to Gilb, October 1982, is used to provide ledger support around the inside perimeter of buildings or at internal concrete or masonry walls. This connector can not be used as a retrofit on the outside of existing houses; it did not tie the sheathing to the top plate and rafter; it did not tie together a rafter and top plate; it did not go around the frieze board; it did not tie into a stud or top plate directly underneath a rafter; and it did not tie together two 2xc3x974""s of the top plate.
The wall tie in United Kingdom patent 2,096,664, to Durrant, October 1982, is used to strengthen mortar joints in brick walls. This connector can not be used as a retrofit on the outside of existing wood houses; it did not tie the sheathing to the top plate and rafter; it did not tie together a rafter and top plate; it did not go around the frieze board; it did not tie into a stud or top plate directly underneath a rafter; and it did not tie together two 2xc3x974""s of the top plate.
The connecting plate for wood members in Germany patent 238,822, to Sauer, March 1986, is used to connect planks, boards, or strips, using bending slots and nail holes. This connector, by its large bending slots, is a weak connector. Bending this connector weakens the metal, especially since most carpenters would hammer the connection to make it fit on planks and boards. This connector is useful for attaching together boards that intersect at odd angles, that is, not equal to 90 or 45 degrees. This connector may be used as a retrofit on existing houses, but was intended for attaching beams and blanks in the skeleton structural framework of new construction. It did not tie the sheathing to the top plate and rafter; it did not go around the frieze board; it did not tie into a stud or top plate directly underneath a rafter; and it did not tie together two 2xc3x974""s of the top plate.
The metal connectors in Switzerland patent 214,358, April 1941 is used to connect wood and metal members together. The connectors can tie I-beams, angle iron, and wood boards to metal frames in skeleton structural framework of new construction. They can not be used as retrofit on existing houses; they did not tie the sheathing to the top plate and rafter; they did not tie the rafter and top plate together; they did not go around the frieze board; and they did not tie together two 2xc3x974""s of the top plate.
The apparatus and method for securing a building during high winds in U.S. Pat. No. 5,319,986 to Winger, June 1994, is used to secure several of the roof rafters to the ground by cables and anchors. This system is employed only when high winds are expected, as the cables must be extended and attached to the ground anchor manually. In a post-and-beam constructed house where the inside rafters are exposed, the cables and attaching hardware are exposed to view. Cables can kink, stretch, rust in place, and break. This system did not tie down the roof sheathing or roof shingles. This system will not work if the homeowner is not home to secure the anchoring cables. It cannot work in areas where tornadoes can occur without warning, especially if the home owner is sleeping or is seeking shelter in the basement or interior room. The system requires extensive and expensive carpentry work and expensive hardware. This system cannot tie into the hot water system or heat hot water by solar energy.
Winger""s U.S. Pat. No. 5,319,896 does not securely tie together the rafter and ridge plate, and tie them straight down to the ground. It cannot use the house foundation as an anchor member. This apparatus is anchored to the ground at an acute angle instead of straight down, which means that more obstructions may be in the way of a ground anchor. Because of the acute angle of the ground anchor, and its angle toward the house, a portable drill could not be used to prepare the hole or install the ground anchor. Because of the acute angle of the ground anchor, it cannot be installed as deep as an anchor that goes straight down.
The house anchor in U.S. Pat. No. 1,864,403, to Bradley, June 1932, uses cables and ground anchors to secure the roof to the ground. This system cannot tie into the hot water system or heat hot water by solar energy. It did not tie together the rafter and ridge plate or tie them straight down to the ground; since the rafter and ridge plate are not secured together and tied to the ground on the gable end of the house, the house is vulnerable to winds on the side of the house that can push or pull and separate the gable end of the rafter plate to ridge plate connection. Cables can stretch and break. Parts of the house anchor include eye-bolts and cable guides which can pull out from wood when subjected to perpendicular pulling forces as from strong winds.
The exterior anchoring apparatus for surface sheets in U.S. Pat. No. 1,864,403, to Bradley, March 1967, uses metal rods and clamps to secure exterior sheathing to a roof. This system cannot be retrofit to an existing roof. It did not tie the sheathing securely to the rafter and ridge board. It does not tie the roof securely to the ground. It did not heat water by solar power.
Objects of this invention are to tie together the roof and supporting structures of an existing building, and to make the structure resistant to strong winds. It is a further object of this invention that the ties be inexpensive and simple. It is a still further object that the invention be simple to install, but have equal or more strength than hurricane ties that are installed on new construction. It is a still further object of this invention that the roof covering, roof sheathing, roof beams, top plate and outside walls of an existing structure be tied together against shear and tensional forces from strong winds.
A further objective is to provide for the installation of this invention on the outside of existing structures. Further objects and advantages of my invention will become apparent from a consideration of the drawings and ensuing description.
These and other objectives of the invention are achieved by a system of simple and economical tie connectors, that tie together the roof covering, roof sheathing, roof beams, top plate, and outside walls of an existing building against shear and tensional forces from strong winds. Several of the ties can be installed by a practical homeowner.
Because this invention can be retro-fitted to the outside of existing structures, it can bring many houses xe2x80x9cup to codexe2x80x9d or greater than new construction that use existing hurricanes ties. The ties do not have to be installed all at once, but can be installed a few at a time as finances require, however, installing all of the ties will provide the most protection against strong winds. In hurricane-prone areas, installation of this invention may decrease insurance premiums.